2004 TOYOTA PRIUS Owners Manual

209
REGENERATIVE BRAKE
When the brake is applied, the electric
motor used as a generator converts kinet-
ic energy into electric energy.
The regenerative brake works in the fol-
lowing operations.1. When the accelerator pedal is re- leased, the reduced speed equal to en-
gine braking in a gasoline −fueled ve-
hicle is obtained in accordance with the
running mode position of the shift le-
ver.
2. When the brake pedal is depressed with the shift lever in “D” or “B”, the
regenerative brake works. HYDRAULIC BRAKE
This brake system has 3 independent hy-
draulic circuits. If either circuit should fail,
the other will still work. However, the ped-
al will be harder to press, and your stop-
ping distance will increase. Also, the
brake system warning light may come on.
CAUTION
Do not drive your vehicle with only a
single brake system. Have your
brakes fixed immediately.
BRAKE ACTUATOR
The brake actuator uses brake fluid pres-
surized by the pump to power
−assist the
brakes. If the brake actuator fails during
driving, the brake system warning light
comes on and buzzer sounds continuous-
ly. In this case, the brakes may not work
properly. If they do not work well, depress
the brake pedal firmly. If the brake system
warning light comes on, immediately stop
your vehicle and contact your Toyota deal-
er. The yellow brake system warning light
may stay on for about 60 seconds after
the “IG
−ON” mode is enabled. It is normal
if the light turns off after a while.
Depressing the brake pedal repeatedly
may turn on the red brake system warning
light and buzzer. It is normal if the light
turns off and the buzzer stops sounding
after a few seconds.
You may hear a small sound in the engine
compartment after the hybrid system is
started or the brake pedal is depressed
repeatedly. This is a pump pulsating
sound of the brake system, and it is not
a malfunction.
In the following conditions, you may hear
a motor sound in the engine compartment.
The brake pedal is depressed when the
hybrid system is turned off.
The driver ’s door is opened.
For a few seconds after the hybrid
system is “OFF” and a bout 90 seconds
have passed.
The brake pedal stroke may be short
when you press the “POWER” switch with
the brake pedal depressed.
Brake system

210
CAUTION
Do not pump the brake pedal if the
hybrid system is not operating.
Each push on the pedal uses up
your reserved brake fluid pressure.
Even if the power assist is com-
pletely lost, the brakes will still
work. But you will have to push the
pedal hard, much harder than nor-
mal. And your braking distance will
increase.
ANTILOCK BRAKE SYSTEM
The antilock brake system is designed
to automatically help prevent lockup of
the wheels during a sudden braking or
braking on slippery road surfaces. This
assists in providing directional stability
and steering performance of the vehicle
under these circumstances.
Effective way to press the ABS brake
pedal: When the anti −lock brake system
function is in action, the slip indicator in
the instrument cluster flashes and you
will hear a noise. In this situation, to let
the anti −lock brake system work for you,
just hold the brake pedal down more
firmly. Do not pump the brake in a panic
stop. This will result in reduced braking
performance.
The anti −lock brake system becomes op-
erative after the vehicle has accelerated
to a speed in excess of approximately 10
km/h (6 mph). It stops operating when the
vehicle decelerates to a speed below
approximately 5 km/h (3 mph). Depressing the brake pedal on slippery
road surfaces such as on a manhole cov-
er, a steel plate at a construction site,
joints in a bridge, etc. on a rainy day
tends to activate the anti
−lock brake sys-
tem.
When the antilock brake system is ac-
tivated, the following condition may oc-
cur. They do not indicate a malfunction
of the system:
You may hear the anti −lock brake sys-
tem operating and the vibrations of the
vehicle body and steering wheel. You
may also hear the motor sound in the
engine compartment even after the ve-
hicle is stopped.

211
CAUTION
Do not overestimate the antilock
brake system: Although the antilock
brake system assists in providing ve-
hicle control, it is still important to
drive with all due care and maintain
a moderate speed and safe distance
from the vehicle in front of you, be-
cause there are limits to the vehicle
stability and effectiveness of steering
wheel operation even with the anti
lock brake system on.
If tire grip performance exceeds its
capability, or if hydroplaning occurs
during high speed driving in the rain,
the antilock brake system does not
provide vehicle control.
Antilock brake system is not de-
signed to shorten the stopping dis-
tance: Always drive at a moderate
speed and maintain a safe distance
from the vehicle in front of you.
Compared with vehicles without an
antilock brake system, your vehicle
may require a longer stopping dis-
tance in the following cases:
Driving on rough, gravel or snow
covered roads.
Driving with tire chains installed.
Driving over the steps such as the
joints on the road.
Driving on roads where the road
surface is pitted or has other differ-
ences in surface height.
Install all 4 tires of specified size at
appropriate pressure: The antilock
brake system detects vehicle speeds
using the speed sensors for respec-
tive wheels’ turning speeds. The use
of tires other than specified may fail
to detect the accurate turning speed,
resulting in a longer stopping dis-
tance.
30p002b
Vehicle sold in U.S.A.
30p007b
Vehicle sold in Canada

212
“ABS” warning light
The light comes on when the “IGON”
mode is enabled. If the antilock brake
system works properly, the light turns
off after the “READY” light comes on.
Thereafter, if the system malfunctions,
the light comes on again.
When the “ABS” warning light is on (and
the brake system warning light is off), the
anti−lock brake system does not operate,
but the brake system still operates con-
ventionally.
When the “ABS” warning light is on (and
the brake system warning light is off), the
anti −lock brake system does not operate
so that the wheels could lock up during
a sudden braking or braking on slippery
road surfaces.
If either of the following conditions oc-
curs, this indicates a malfunction some-
where in the components monitored by
the warning light system. Contact your
Toyota dealer as soon as possible to
service the vehicle.
The light does not come on when the
“IG −ON” mode is enabled, or the
“READY” light remains on.
The light comes on while you are driv-
ing. A warning light turning on briefly during
operation does not indicate a problem.
CAUTION
If the “ABS” warning light remains on
together with the red brake system
warning light, immediately stop your
vehicle at a safe place and contact
your Toyota dealer.
In this case, not only the antilock
brake system will fail but also the
vehicle will become extremely unsta-
ble during braking.
Either of the following conditions may
occur, but does not indicate a malfunc-
tion:
The light may stay on for about 60
seconds after the “IG
−ON” mode is en-
abled. It is normal if it turns off after
a whi l e.
Depressing the brake pedal repeatedly
may turn on the light. It is normal if
it turns off after a few seconds. BRAKE ASSIST SYSTEM
When you slam the brakes on, the
brake assist system judges as an emer-
gency stop and provides more powerful
braking for a driver who cannot hold
down the brake pedal firmly.
When you slam the brakes on, more pow-
erful braking will be applied. At this time,
you may hear a sound in the engine
compartment. This does not indicate a
malfunction.
The brake assist system becomes opera-
tive after the vehicle has accelerated to
a speed in excess of approximately 10
km/h (6 mph). It stops operating when the
vehicle decelerates to a speed below
approximately 5 km/h (3 mph).
For an explanation of this system’s warn-
ing light, see “Service reminder indicators
and warning buzzers” on page 117.

213
The electric power steering system, us-
ing an electric motor, assists the turn-
ing of the steering wheel.
In the following cases, you may feel the
steering becomes heavy. However, the
electric power steering system warning
light does not come on. (Because it is
not a malfunction.)
When maneuvering the steering fre-
quently or keeping the steering wheel
turned fully while the vehicle is stopped
or moving very slowlyThe power steering effect will be re-
duced to prevent the system from over-
heating. Avoid turning the steering
wheel, or stop the vehicle. When you
leave the vehicle in the “IG −ON” mode
for a while, the system will become
cool.
NOTICE
If you repeat the operation which will
turn on the overheating prevention
function, the electric power steering
system may be damaged.
When the auxiliary battery is dis-
charged
Check the auxiliary battery’s condition.
If necessary, recharge or replace the
battery. For details, see “Checking aux-
iliary battery condition” on page 298.
When the steering wheel is operated
with the hybrid system not to be turned
on (with the “READY” light off)
The auxiliary battery capacity is de-
creased temporarily. The system re-
turns to normal some time after the
hybrid system is turned on.
If there is a problem somewhere in the
electric power steering system, the warn-
ing light comes on in the multi −information
display. For details, see “Multi −information
display” on page 124.30p003
The brake pad wear limit indicators on
your disc brakes give a warning noise
when the brake pads are worn to where
replacement is required.
If you hear a squealing or scraping noise
while driving, have the brake pads
checked and replaced by your Toyota
dealer as soon as possible. Expensive ro-
tor damage can result if the pads are not
replaced when necessary.
Electric power steering system Brake pad wear limit
indicators

214
30p004b
The vehicle identification number (VIN)
is the legal identifier for your vehicle.
This number is on the left top of the
instrument panel, and can be seen
through the windshield from outside.
This is the primary identification number
for your Toyota. It is used in registering
the ownership of your vehicle.
30p005b
The vehicle identification number (VIN) is
also on the Certification Label.
30p006b
Engine number
Motor number
The engine and motor number plates
are installed on the engine and trans-
axle case as shown.
Your Toyota’s identification—
—Vehicle identification
number —Engine and motor number

215
Theft prevention labels
Your new vehicle carries theft preven-
tion labels which are approximately 47
mm (1.85 in.) by 12 mm (0.47 in.).
The purpose of these labels is to reduce
the incidence of vehicle thefts by facilitat-
ing the tracing and recovery of parts from
stolen vehicles. The label is designed so
that once it is applied to a surface, any
attempt to remove it will result in destroy-
ing the integrity of the label. Transferring
these labels intact from one part to anoth-
er, will be impossible.
NOTICE
You should not attempt to remove the
theft prevention labels as it may vio-
late certain state or federal laws.
CAUTION
Do not modify the suspension/chassis
with lift kits, spacers, springs, etc. It
can cause dangerous handling charac-
teristics, resulting in loss of control.
Suspension and chassis

216This illustration indicates typical tire
symbols.
1. Tire size— For details, see “Tire
size” on page 218.
2. DOT and Tire Identification Number (TIN)— For details, see
“DOT and Tire Identification Num-
ber (TIN)” on page 217.
3. Location of tread wear indica- tors— For details, see “Checking
and replacing tires” on page 291.
4. Tire ply composition and materi- als— Plies mean a layer of rubber −
coated parallel cords. Cords mean
the strands forming the plies in the
tire.
5. Summer tire or all season tire— An all season tire has “M+S”
on the sidewall. A tire not marked
with “M+S” is a summer tire. For
details, see “Types of tires” on
page 227.
Tire information—
—Tire symbols
30p101